As the weather warms and the days grow longer here in the United States, you’re preparing for the planting season. But, before you rush out of the house and sow some seeds in the ground, you might want to consider preseason irrigation. Preseason irrigation, also known as preplant irrigation, is the application of water during fallow periods in order to help seed germination and early plant growth.
Studies investigating irrigation practices in the 1980s and 1990s generally concluded that in-season irrigation was more practical than preseason irrigation due to the fact that winter precipitation could replenish the soil water profile. However, due to recent drought conditions, winter precipitation has not provided the necessary moisture required for preparation of the planting season. A rootzone soil moisture map (below), created on April 8th by scientists at NASA’s Goddard Space Flight Center, shows below-average conditions throughout the central and southwestern United States.
A recent study1 in Kansas demonstrated that preseason irrigation amounts of 1.5 inches (applied separately in two passes several days apart with a sprinkler pivot) increased maize grain yields by an average of 16 bushels/acre. These returns were greatest when in-season irrigation amounts were limited to 0.7 inches/week and when planting densities were 27,500 plants/acre. Therefore, if water restrictions are tight this year, preseason irrigation may prove to be a successful strategy for you.
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1. Schlegel, A. J., Stone, L. R., Dumler, T. J., and Lamm, F. R. 2012. Managing diminished irrigation capacity with preseason irrigation and plant density for corn production. Transactions of the ASABE. 55(2): 525-531.